US5873924A - Desulfurizing mix and method for desulfurizing molten iron - Google Patents

Desulfurizing mix and method for desulfurizing molten iron Download PDF

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Publication number
US5873924A
US5873924A US08/826,880 US82688097A US5873924A US 5873924 A US5873924 A US 5873924A US 82688097 A US82688097 A US 82688097A US 5873924 A US5873924 A US 5873924A
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US
United States
Prior art keywords
iron
desulfurizing
lime
molten iron
alumina
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Expired - Fee Related
Application number
US08/826,880
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English (en)
Inventor
Brian Mark Kinsman
Leon A. Luyckx
James H. Young, Jr.
Robert V. Branion, Jr.
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Magnesium Technologies Corp
United States Steel Corp
Original Assignee
Reactive Metals and Alloys Corp
United States Steel Corp
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Priority to US08/826,880 priority Critical patent/US5873924A/en
Application filed by Reactive Metals and Alloys Corp, United States Steel Corp filed Critical Reactive Metals and Alloys Corp
Assigned to USX CORPORATION reassignment USX CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: BRANION, ROBERT V., JR.
Assigned to REACTIVE METALS & ALLOYS CORPORATION reassignment REACTIVE METALS & ALLOYS CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: YOUNG, JAMES H., JR., KINSMAN, BRIAN MARK, LUYCKX, LEON A.
Assigned to NATIONAL CITY COMMERCIAL FINANCE, INC. reassignment NATIONAL CITY COMMERCIAL FINANCE, INC. SECURITY AGREEMENT Assignors: REACTIVE METALS & ALLOYS CORPORATION
Priority to BR9809070-4A priority patent/BR9809070A/pt
Priority to CA002286221A priority patent/CA2286221C/fr
Priority to PCT/US1998/006781 priority patent/WO1998045484A1/fr
Priority to EP98914521A priority patent/EP0973951A1/fr
Priority to AU68858/98A priority patent/AU6885898A/en
Priority to US09/084,657 priority patent/US5972072A/en
Publication of US5873924A publication Critical patent/US5873924A/en
Application granted granted Critical
Assigned to ROSSBOROUGH-REMACOR, LLC reassignment ROSSBOROUGH-REMACOR, LLC ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: REACTIVE METALS & ALLOYS CORPORATION
Assigned to HUNTINGTON NATIONAL BANK, THE reassignment HUNTINGTON NATIONAL BANK, THE SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ROSSBOROUGH-REMACOR, LLC
Assigned to MAGNESIUM TECHNOLOGIES CORP. reassignment MAGNESIUM TECHNOLOGIES CORP. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ROSSBOROUGH-REMACOR, LLC
Assigned to BANK OF MONTREAL reassignment BANK OF MONTREAL SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: MAGNESIUM TECHNOLOGIES CORPORATION
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C1/00—Refining of pig-iron; Cast iron
    • C21C1/02—Dephosphorising or desulfurising
    • C21C1/025—Agents used for dephosphorising or desulfurising
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C1/00—Refining of pig-iron; Cast iron
    • C21C1/02—Dephosphorising or desulfurising

Definitions

  • the invention relates to a desulfurizing composition and method for desulfurizing molten pig iron, cast iron and malleable iron.
  • molten iron from the blast furnace is desulfurized by the injection of a suitable reagent with a carrier gas, usually nitrogen.
  • a suitable reagent with a carrier gas, usually nitrogen.
  • One widely used desulfurizing reagent is a mixture of particulate lime and particulate magnesium. Although this reagent performs well as a desulfurizer, steelmakers have been seeking alternative reagents. This search has been prompted by the facts that magnesium lime reagents are flammable and that metallic magnesium, which may be 90% of this mix, is quite costly.
  • a desulfurization composition containing from about 3% to about 20% particulate metallic aluminum, about 5% to about 30% particulate alumina, about 0.5% to about 12% particulate hydrocarbon material or other gas generating composition and the balance lime plus impurities.
  • aluminum dross as the source of aluminum and alumina, but other sources of aluminum and alumina could be used.
  • the desulfurization composition is injected into molten iron from a blast furnace preferably in an amount of 4 to 20 pounds desulfurizer per ton of hot metal.
  • the desulfurizing composition can be injected into the hot metal through a lance using a carrier gas or dumped into the hot metal as it is being poured into the ladle. At least for torpedo ladles, the desulfurization composition can be placed in the ladle before the hot metal is poured into it.
  • the resulting torpedo ladle slag or transfer ladle slag also has to become in major part a calcium aluminate slag, preferably as close as possible to lime saturation to achieve sulfur partition ratios at or about 200-500 to 1.
  • Additional oxides such as SiO 2 (Up to 15%) and MgO (up to 7%) tend to improve the fluidity and lower the melting points of these calcium aluminates and are inherited from carried-over blast furnace slags.
  • composition of this gas be at least neutral such as nitrogen or, preferably reducing, such as hydrocarbons, cracking instantly into reducing hydrogen gas and elemental carbon.
  • composition and method use no magnesium and no calcium carbide but rely upon the intimate mixing of aluminum metal, alumina and hydrocarbons with/or without other natural or reducing gas generating ingredients in such proportions as to provide excess CaO, the formation of a CaO--Al 2 O 3 , liquid compounds to absorb and dilute CaS and the formation in situ of the correct amount of "micro-bubbles" to increase metal-to-blend mass contact during the ascension of the injected blend to the surface of the bath.
  • the whole process guarantees a sufficient sulfur partition ratio in the top slag to prevent secondary reversion of the removed sulfur.
  • Our preferred composition contains aluminum dross as the source of aluminum and alumina. Since our composition range based upon aluminum dross is significantly lower in cost than magnesium, pure aluminum and calcium carbide, our composition is relatively inexpensive per unit sulfur removed per net ton of hot metal treated. We estimate that the total reagent cost of our composition will be about 30% less than the total reagent cost of the conventional 90% magnesium, 10% lime reagent, co-injected with lime to yield 20% to 25% overall magnesium content.
  • our desulfurizing composition and method lead to vastly improved deslagging capability and time and reduced iron losses.
  • our composition and method reduce sulfur reversion after blow in the subsequent BOF operations because of better slag skimming efficiency.
  • FIG. 1 is a graphical presentation of individual data points and regression lines showing the degree of desulfurization possible with the present invention reagent.
  • FIG. 2 is a graphical presentation showing the effect of adding magnesium to the present invention reagent in relationship to the population of data points obtained without magnesium.
  • the composition of the present invention is based on lime as the primary component and contains aluminum, alumina, and a non-oxidizing gas generating additive.
  • the aluminum and alumina are preferably in the form of aluminum dross.
  • the non-oxidizing gas generating additive will be a reducing gas generating additive based on a hydrocarbon component.
  • soda ash could be used.
  • the composition of the reagent is in the following concentration, the total weight being 100 percent.
  • the process for using the reagent described above consists of adding the reagent to molten iron by injection with a carrier gas, typically through a lance as deeply as possible within the bath.
  • the reagent may be added in whole as a blend or may be added separately or in combination from individual storage and injection vessels so as to approximately match the preferred blend composition above as closely as possible. Additionally, when injecting separately or in combination from separate vessels, the ratios of the components may be varied in order to vary the composition of the material exiting the lance tip throughout the course of the injection or to introduce the components in sequence.
  • torpedo ladles it is possible to add the reagent while the hot metal is being poured from the blast furnace or place sufficient reagent in the torpedo ladle before pouring. Movement of the hot metal as it fills the torpedo ladle will mix the reagent into the molten bath.
  • the injection rate of the blend or combined injection rates of the individual components is typically 50 to 250 pounds per minute but may vary widely depending on the size and geometry of the hot metal ladle, quantity of iron in the ladle, depth of iron in the ladle, freeboard in the ladle, time permitted for the injection or any combination of these factors.
  • the injection rate is somewhat slower due to the geometry and depth of iron factors listed above and generally falls within the range of 50 to 150 pounds per minute.
  • For transfer ladle injection processes the injection rate is generally higher, between 150 and 250 pounds per minute because of the depth of iron involved. It should be noted that because this reagent does not utilize any magnesium, reaction turbulence is practically non-existent.
  • injection rates can be increased over standard lime, magnesium injection rates. It is common practice to utilize as little carrier gas as possible in order to cause a uniform injection of the solids throughout the complete injection, with higher carrier gas flow rates at the beginning and end of the injection cycle in order to keep the lance tip free from obstruction.
  • the amount of aluminum dross required will depend from the composition of the dross. We have used aluminum dross containing about 50% Al, about 30% Al 2 O 3 and the balance impurities. Another suitable dross contained about 20% Al, 55% Al 2 O 3 and the balance impurities. Similarly, the amount of hydrocarbon or other gas generator will also vary according to the material used. We prefer to provide 0.5% to 5% gilsonite, a tertiary coal containing about 80% hydrocarbons. One could also use low sulfur, high volatile coal, polyethylene, polypropelene or ground rubber tires. We prefer not to use vinyls because of their chloride content.
  • Tables 1 to 3 show the degree of desulfurization obtained by injection of different quantities of the blended reagent into molten iron.
  • Table 1 presents results from a torpedo ladle process described in Example 1.
  • Table 2 contains results from a transfer ladle process described in Example 2.
  • Table 3 shows a comparison of process results obtained by the use of this reagent versus a normal magnesium reagent at the same transfer ladle process described in Example 3.
  • Table 4 gives the results of the same transfer ladle process described in Example 2 except that magnesium was added to the reagent.
  • the blended reagent composition was as follows:
  • the reagent was injected through a refractory lance at about 90 to 110 pounds per minute into torpedo ladles varying in size from nominal capacity of 150 tons of hot metal to 260 tons of hot metal.
  • Samples of iron were obtained prior to the reagent being injected and analyzed for sulfur concentration using a LECO Sulfur Analyzer.
  • Predetermined quantities of the reagent were injected followed by a second sulfur analysis in order to determine the degree of desulfurization obtained.
  • the torpedo ladle was moved to another position to continue the desulfurization process using a lime and magnesium based reagent as required by the steelmaking facility.
  • the blended reagent composition was as follows:
  • the reagent was injected through a refractory lance at about 140 to 180 pounds per minute into a transfer ladle with a nominal capacity of about 320 tons of hot metal.
  • Samples of iron were obtained prior to the reagent being injected and analyzed for sulfur concentration using a LECO Sulfur Analyzer. Based on the experience from Example 1 an equation was derived that produced the necessary quantity of reagent that would need to be injected in order to obtain the degree of desulfurization to meet the final sulfur specifications of the hot metal for the steelmaking process.
  • a sample of iron was obtained and analyzed prior to the injection and again after the reagent injection in order to determine the degree of desulfurization obtained. Results were such that it was not necessary to continue the desulfurization process using a lime and magnesium based reagent as in Example 1.
  • the lower amounts of spent slag raked off can be attributed to two reasons.
  • Table 3 also compares the sulfur pickup during the oxygen steelmaking process after using this reagent and after the normal lime and magnesium reagent. With all other factors remaining the same (scrap sulfur content, steelmaking flux sulfur content and steelmaking practice) the lower sulfur pickup can be attributed to the characteristics of the slag that permits a more efficient slag removal.
  • the blended reagent composition was as follows:
  • Table 4 shows the degree of desulfurization obtained with the reagent and FIG. 2 portrays the degree of desulfurization in relationship to the present invention reagent. It can be seen that the addition of magnesium does not aid in increasing the degree of desulfurization with this reagent, the points being part of the same population as data obtained with the reagent described in Example 3. As described earlier, magnesium is consumed by oxygen liberated from the CaO+S reaction, and the addition of magnesium to this reagent could be considered an expensive waste.
  • the desulfurizing compositions may inject a non-oxidizing gas into the hot metal with the desulfurizer. This gas must be injected in a manner to provide sufficient agitation in the molten metal to obtain the desired degree of desulfurization.
  • the desulfurizing composition used in this method would contain 10% to 60% aluminum dross and the balance lime or 5% to 30% aluminum, 5% to 30% alumina and the balance lime.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
US08/826,880 1997-04-07 1997-04-07 Desulfurizing mix and method for desulfurizing molten iron Expired - Fee Related US5873924A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US08/826,880 US5873924A (en) 1997-04-07 1997-04-07 Desulfurizing mix and method for desulfurizing molten iron
BR9809070-4A BR9809070A (pt) 1997-04-07 1998-04-06 Mistura dessulfurante e método para dessulfurar ferro fundido
CA002286221A CA2286221C (fr) 1997-04-07 1998-04-06 Melange de desulfuration et procede de desulfuration de fonte en fusion
PCT/US1998/006781 WO1998045484A1 (fr) 1997-04-07 1998-04-06 Melange de desulfuration et procede de desulfuration de fonte en fusion
EP98914521A EP0973951A1 (fr) 1997-04-07 1998-04-06 Melange de desulfuration et procede de desulfuration de fonte en fusion
AU68858/98A AU6885898A (en) 1997-04-07 1998-04-06 Desulfurizing mix and method for desulfurizing molten iron
US09/084,657 US5972072A (en) 1997-04-07 1998-05-26 Desulfurizing mix

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US08/826,880 US5873924A (en) 1997-04-07 1997-04-07 Desulfurizing mix and method for desulfurizing molten iron

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US09/084,657 Division US5972072A (en) 1997-04-07 1998-05-26 Desulfurizing mix

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US09/084,657 Expired - Fee Related US5972072A (en) 1997-04-07 1998-05-26 Desulfurizing mix

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EP (1) EP0973951A1 (fr)
AU (1) AU6885898A (fr)
BR (1) BR9809070A (fr)
CA (1) CA2286221C (fr)
WO (1) WO1998045484A1 (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1059360A2 (fr) * 1999-06-07 2000-12-13 Kawasaki Steel Corporation Procédé de désulfuration de fer en fusion
WO2001073138A2 (fr) * 2000-03-24 2001-10-04 Qual-Chem Limited Élaboration d'acier
US6372013B1 (en) 2000-05-12 2002-04-16 Marblehead Lime, Inc. Carrier material and desulfurization agent for desulfurizing iron
US20050092133A1 (en) * 2000-06-14 2005-05-05 Nkk Corporation Method for manufacturing hot metal desulfurizing agent and apparatus for same
US20060150775A1 (en) * 2004-12-07 2006-07-13 Nu-Iron Technology, Llc Method and system for producing metallic iron nuggets
EP3072853A1 (fr) * 2015-03-24 2016-09-28 Real Alloy Germany GmbH Procédé de fabrication d'oxyde d'aluminium calciné
CN113388716A (zh) * 2021-05-24 2021-09-14 鞍钢股份有限公司 一种无氟复合型铁水脱硫剂及制备方法
CN113403451A (zh) * 2021-05-24 2021-09-17 鞍钢股份有限公司 一种无氟铁水脱硫用球形渣及制备方法

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DE19857733A1 (de) * 1998-12-15 2000-06-21 Almamet Gmbh Entschwefelungsmittel
US6287774B1 (en) 1999-05-21 2001-09-11 Caliper Technologies Corp. Assay methods and system
DE10351686A1 (de) * 2003-11-06 2005-06-09 Sachtleben Chemie Gmbh Verfahren zum Einbringen von anorganischen Festkörpern in heiße, flüssige Schmelzen
US7731778B2 (en) * 2006-03-27 2010-06-08 Magnesium Technologies Corporation Scrap bale for steel making process
WO2009004565A2 (fr) * 2007-07-02 2009-01-08 Bumatech (Pty) Limited Fondant et son procédé de fabrication
DE102010027964A1 (de) * 2010-04-20 2011-10-20 Deere & Company Hydraulische Anordnung
US9322073B1 (en) 2013-03-14 2016-04-26 ALMAMET USA, Inc. Preparation of flux lime for a BOF converter including conversion of troublesome fines to high quality fluidized lime
WO2016182892A1 (fr) 2015-05-14 2016-11-17 Epps Larry J Procédé et appareil améliorés pour l'élimination de laitier pendant un traitement de métal
WO2016205312A1 (fr) 2015-06-17 2016-12-22 Epps Larry J Lance d'agitation de matériau coaxiale et son procédé d'utilisation
US10344343B2 (en) 2016-06-15 2019-07-09 Larry J Epps Multiple chamber material-stirring lance and method

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US4266969A (en) * 1980-01-22 1981-05-12 Jones & Laughlin Steel Corporation Desulfurization process
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US5397379A (en) * 1993-09-22 1995-03-14 Oglebay Norton Company Process and additive for the ladle refining of steel

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Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1059360A2 (fr) * 1999-06-07 2000-12-13 Kawasaki Steel Corporation Procédé de désulfuration de fer en fusion
EP1059360A3 (fr) * 1999-06-07 2001-06-06 Kawasaki Steel Corporation Procédé de désulfuration de fer en fusion
US6379425B1 (en) 1999-06-07 2002-04-30 Kawasaki Steel Coporation Method of desulfurizing molten iron
WO2001073138A2 (fr) * 2000-03-24 2001-10-04 Qual-Chem Limited Élaboration d'acier
WO2001073138A3 (fr) * 2000-03-24 2002-03-14 Qual Chem Ltd Élaboration d'acier
US6372013B1 (en) 2000-05-12 2002-04-16 Marblehead Lime, Inc. Carrier material and desulfurization agent for desulfurizing iron
US20050092133A1 (en) * 2000-06-14 2005-05-05 Nkk Corporation Method for manufacturing hot metal desulfurizing agent and apparatus for same
US20060150775A1 (en) * 2004-12-07 2006-07-13 Nu-Iron Technology, Llc Method and system for producing metallic iron nuggets
US7641712B2 (en) * 2004-12-07 2010-01-05 Nu-Iron Technology, Llc Method and system for producing metallic iron nuggets
US20100164150A1 (en) * 2004-12-07 2010-07-01 Nu-Iron Technology, Llc Method and system for producing metallic iron nuggets
US8158054B2 (en) 2004-12-07 2012-04-17 Nu-Iron Technology, Llc Method and system for producing metallic iron nuggets
EP3072853A1 (fr) * 2015-03-24 2016-09-28 Real Alloy Germany GmbH Procédé de fabrication d'oxyde d'aluminium calciné
CN113388716A (zh) * 2021-05-24 2021-09-14 鞍钢股份有限公司 一种无氟复合型铁水脱硫剂及制备方法
CN113403451A (zh) * 2021-05-24 2021-09-17 鞍钢股份有限公司 一种无氟铁水脱硫用球形渣及制备方法

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Publication number Publication date
US5972072A (en) 1999-10-26
AU6885898A (en) 1998-10-30
WO1998045484A1 (fr) 1998-10-15
CA2286221C (fr) 2003-02-04
CA2286221A1 (fr) 1998-10-15
EP0973951A1 (fr) 2000-01-26
BR9809070A (pt) 2000-08-08

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